Circular Polarization Purity in Antenna Arrays via Incremental Clocking
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Solution Overview
Problem
Circularly polarized antennas often exhibit significant polarization ellipticity due to elliptical radiation, leading to interference and compromised isolation, as individual elements produce waves that are more elliptical than purely circular, making it costly and impractical to achieve circular polarization.
Innovation Solution
An array of elliptically polarized elements is incrementally clocked relative to each other around their direction of propagation, with compensating line lengths in the feed to mitigate phase shifts, ensuring a combined output that is substantially circularly polarized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual antenna elements are designed to produce circularly polarized waves, then the polarization purity is improved, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent divides the antenna system into multiple simpler elements that each produce elliptically polarized waves, rather than requiring each element to produce pure circular polarization. By segmenting the polarization correction function across multiple elements with different orientations, the system achieves circular polarization at the array level rather than at the individual element level, reducing manufacturing complexity while maintaining polarization purity.
Solution Approach 2:
The patent combines multiple elliptically polarized waves from differently oriented elements to produce a resultant circularly polarized wave. The merging of these simpler individual contributions at the array level achieves the same effect as complex individual circularly polarized elements, but with reduced manufacturing difficulty for each element.
2Manufacturing precision
If elements are clocked at different orientations, then the combined output circular polarization is improved, but the phase shift complexity increases
Solution Approach 1:
The patent changes the orientation parameter (clocking angle) of each element in the array while using simpler feed networks. By adjusting the spatial orientation parameter of multiple elements with identical or simple feed structures, the system achieves circular polarization without requiring complex phase shifting networks, thus reducing phase shift complexity while improving polarization purity.
3Reliability
If compensating line lengths are added to feeds, then the phase shift is reduced, but the device complexity increases
Solution Approach 1:
The patent applies different compensating line lengths to specific feeds based on their local orientation and position in the array, rather than using a uniform complex phase correction system across all elements. This localized approach to phase compensation achieves proper phase alignment for each element's contribution to the circular polarization while minimizing overall device complexity.
Data Source
AI summary
Ellipticity reduction in circularly polarized array antennas is provided herein. An antenna array may include a processor that is configured to control a plurality of elements, each of the plurality of elements producing an elliptically polarized wave having an eccentricity value, the elliptically polarized wave traveling along a direction of propagation, wherein at least a portion of the plurality of elements are incrementally clocked around their direction of propagation, so that a combined output of the plurality of elements is substantially circularly polarized.